1. Field of the Invention
This invention relates to covers used in wall or ceiling openings in buildings to prevent loss of heat during cold weather and loss of cool air during hot weather that is otherwise caused by a poorly insulating door that is used to close the opening.
2. Description of the Related Art
Rather than an in-ceiling attic opening, some homes have walk-through or crawl-through openings, some with doors (usually mounted in a generally vertical orientation), for access to an attic space. When such an opening has a door, it may be an ordinary, full-sized door, mounted on hinges within a door frame, as are mounted most interior household doors. In other situations such a door may be as simple as a piece of plywood or other material that has been cut to fit into a wall opening and which may be held in the opening by a latch, but often is not mounted on hinges. Often such a door, whether full-sized or not, has no additional insulation within or about it, including not having any sort of weather-stripping around its edges, where it contacts the door frame or the wall. Such a door usually provides a substantial breach to the otherwise encompassing insulation of the home or other building. A plywood door typically has an insulating R-value of 0.5 or less, while commonly the remainder of the attic has insulation with an R-value significantly greater.
There have been a number of inventions to date that have addressed this problem, though primarily in connection with in-ceiling openings. The inventions primarily address the problem with two main approaches, one- and two-piece covers.
There are a number of one-piece covers. U.S. Pat. No. 4,299,059 discloses a ceiling door that is insulated and to which an attic ladder is attached. U.S. Pat. No. 4,151,894 discloses a one-piece cover for an attic opening that fits over the attic door. It is double walled and able to contain a layer of insulation. U.S. Pat. No. 4,281,743 similarly provides a one-piece cover for an attic opening that fits over the attic door. This cover, however, is a shell, comprised of multiple pieces that need to be assembled in a tongue and groove design into which insulating panels are inserted. U.S. Pat. No. 5,475,955 discloses a two-piece shell that is able to contain insulation. U.S. Pat. No. 4,832,153 is also a one-piece cover for an attic opening. This cover consists of detachable components that can be stored or attached with assembly components to serve as an insulating cover. U.S. Pat. No. 4,928,441 discloses an inverted tub shaped cover that is hinged to an attic floor. U.S. Pat. No. 5,271,198 discloses a compartmentalized plastic or fiberboard shell with a moisture barrier insert that can accommodate insulation. U.S. Pat. No. 5,628,151 discloses a one-piece shell with multiple pockets that can hold insulation.
There have also been other two-piece covers. U.S. Pat. No. 4,344,505 discloses a stationary frame with a hinged door that opens to an upright position. The door and frame are made of insulated material and covered with wood furring for securing the hinges to the door and frame. The door merely rests on the frame. U.S. Pat. No. 4,591,022 discloses a frame and door, but the door is in three pieces. In order to open the door, it collapses in an accordion manner to gain access to the attic. The frame consists of components that are attached and secured to the attic floor with hinges.
U.S. Pat. No. 4,312,423 discloses an all in one approach for a ladder, insulating cap and packaging container.
With each patent, there are some consistent elements. Each patent referenced above is not in itself an insulating solution. Rather, it is a shell made of various materials into which one can insert insulation. Thereafter, each solution has distinguishing ways to affix the cover to the attic and open the cover to access the attic. The shells require some assembly.